Depends on your approval, I had every companion stay except for Blackwall (who I sentenced to become a Warden) and the obvious 2, Solas and the Divine (in my case it was icky Vicky for some reason). Dorian first told me in the library that after the crisis he was planing on going back and trying to make Tevinter better, and that my character inspired him to do so. After the final battle he said that he has his best friend in the world (my inquisitor) at Skyhold and he was going to stay. Even Varric told me that he was going to stay for as long as he could, he had to at least get in "one more good round of Wicked grace, and try to help the commander win some of his dignity back". I had enough approval with Sera that she said that she didn't want to go back to Oralis, and my Inquisitor told her that she was like family and that Skyhold was her home therefore she could stay for as long as she wanted. Cassandra was my Inquisitor's love interest, she said that she would always stand at my Inquistor's side, the way she said it made me predict wedding bells in the future (if the writers allow it) lol.